I'm just starting to look at fashrom to see how to read/update SPI flash on a PCIe card

There isn't much from Via but the chipset is used in the Raspberry Pi 4 and the Pi firmware provides a flash tool vl805 (no source code of course!)

I can run it on Intel with Qemu - unfortunately for me the tool is hard coded for a different SPI flash chip (and in later Pi hardware seems to have been moved/removed)

Inspecting the board and related datasheets (VL800) the chipset has an SPI interface for firmware, and it can be used for PCI BIOS apparently.  The actual SPI chip varies from board to board - mine is FM25Q04 from the data sheet ID=A112. Raspberry Pi seems to use W25X10BV  based on the ID EF10

Are there any simple examples of accessing SPI on PCIe cards?

sorry for the long post - I've included a bit  more info on what I could find on the chip

thanks

John Paul

Other info on the chip:

I can  read the firmware version easily:

sudo lspci -d 1106:3483 -xxx | awk '/^50:/ { print "VL805 FW version: " $5 $4 $3 $2 }'

I can use strace to see what vl805 doing - I can make out some SPI commands - here it reads the SPI flash chip ID:

(bunch of reads/writes)

I was able to find a Windows based firmware updater which supports about 20 different SPI chips - people have reported adding new chipsets, looks like I have to add mine as well. 

The flash tool runs under wine but it can't read anything - will have to find a fix or run in a vm.

Via SpiFlash.ini:

[MX25L512]

Raspberry Pi 4 ?

PageSize=10